1. The Field of the Invention
This invention relates to a composition for removing stains on textiles. More particularly this invention relates to a composition of n-methylpyrrolidone and another co-solvent to effectively and safely removing ink from carpets.
2. The Relevant Art
Inks, lipstick, lacquer based polishes and/or paints (“residues”) have historically been a bane to the existence of carpet owners. This is primarily due to the fact that these products, such as fingernail polish, contain resins that form hard residues when allowed to dry. When left to dry on a textile, such as carpet, the extraction of these resins can be extremely difficult and potentially damaging to the textile itself.
A handful of organic compounds have been identified which have been successfully used as broad spectrum solvents in removing the residues. Unfortunately, the great majority of these have ultimately been found to present undesirable toxicologies and serious hazards to the environment; examples of these compounds include methylene chloride and methyl ethyl ketone (MEK), as well as toluene, xylene, and other aromatics, many of which include the additional hazard of high flammability. For example, although MEK has long been considered a satisfactory solvent from the standpoint of cleaning effectiveness, there is a growing concern that the toxicity and flammability of MEK exposes users to unnecessary risks. Also, because used MEK is considered a threat to the environment, and so is classified as a hazardous waste, the expense associated with the safe disposal of MEK is on the order of 5-10 times greater than the amount which the user initially pays for the solvent. Moreover, because of its relatively high vapor pressure, the loss of MEK to the atmosphere during use is excessive, necessitating the use of large and expensive collection systems such as vacuum hoods.
Because of the concern for the safety, health, and environmental hazards which these known organic solvents thus present, both the federal and state governments are promulgating increasingly stringent criteria which solvent users must comply with. For instance, the California State Legislature limits the use of volatile solvents by requiring that they have a vapor pressure below about 45 mmHg at twenty degrees Celsius. In addition, regulations require that solvents be disposed of in a manner that will not adversely affect the environment. For many users of such solvents, this disposal generally translates into increased operating costs, as noted above.
For the above reasons, a primary consideration for many users of organic solvents has become the toxicity of a particular solvent mixture, and also the hazards which it presents to the environment. This has lead to a number of attempts to find safe substitutes for the hazardous organic solvents which have been used in the past. As an example, methylene chloride has been widely used in industry, especially for formulating paint strippers, lacquer removers, and paint clean-up systems, but it suffers from high volatility which leads to excessive evaporation, contributing to worker exposure and environmental pollution.
Attempts have consequently been made to replace methylene chloride using various, safer organic solvents, but for the most part the replacement solvents create additional problems. Many of the solvents suitable for dissolving oil-based compounds are volatile. These solvents tend to evaporate before they have had sufficient contact time with the affected area and the dissolution process fails. Furthermore, many of these volatile solvents are flammable, which makes suction of the solvent into non-spark proof wet vacuums dangerous. As a result, methods utilizing volatile solvents typically involve blotting or rubbing the treated area, which are much less effective and much more labor intensive than suction techniques.
For example, n-methylpyrrolidone (NMP) has sometimes been found to be a suitable substitute for MEK or methylene chloride in terms of its solvent abilities and it exhibits a very low volatility, which drastically reduces the flammability hazard and evaporative losses. However, NMP alone is sometimes excessively harsh for many applications in that it may cause damage to the underlying substrate. Other compositions of n-methylpyrrolidone include a plant or animal-derived oil as an essential component.
Under the typical and well-known polish extraction techniques, NMP is poured over the affected area in order to dissolve and soften the residue. A commonly recognized aspect of this process is to ensure that the NMP remains in continuous contact with the residue in order to fully dissolve the same. However, prolonged contact of the NMP with the textile may cause a latex adhesive or similar fabric backing to delaminate. This is a common problem resulting from applying such solvents to carpets because typical latex adhesives that bind carpet fibers to the carpet backing material can be degraded relatively quickly by overexposure to the solvent. Too little NMP is not effective at removing stains.
Thus, it can be clearly recognized that there is a need for composition for safely removing stains from textiles, such as carpet, that does not damage the affected textile, and a method for accomplishing the same.